U.S. patent number 4,863,101 [Application Number 07/208,659] was granted by the patent office on 1989-09-05 for accelerating slugs of liquid.
This patent grant is currently assigned to ACB Technology Corporation. Invention is credited to Aubrey C. Briggs, Larry L. Pater.
United States Patent |
4,863,101 |
Pater , et al. |
September 5, 1989 |
Accelerating slugs of liquid
Abstract
Discrete volumes, or slugs, of liquid are accelerated to high
velocities utilizing energy stored by compressing the liquid.
Liquid is forced into a pressure vessel already filled with liquid
to effect the compression. A slug of liquid is ejected from the
pressure vessel into a cumulation nozzle by the energy stored in
the compressed liquid when a valve is rapidly opened. The valve is
unseated when an unseating force exceeds a closing bias. The valve
is then opened rapidly by an opening force generated by the
compressed liquid. By repetitively introducing highly pressurized
liquid into the pressure vessel, the valve automatically cycles to
generate a series of pulsed liquid jets. Rapid opening of the valve
is aided by an extension on the valve member which sealingly slides
inside the passage of the cumulation nozzle to block release of
liquid until the valve member accelerates sufficiently that the
required opening rate is achieved as the extension clears the
nozzle passage.
Inventors: |
Pater; Larry L. (Zelienople,
PA), Briggs; Aubrey C. (Rosslyn Farms, PA) |
Assignee: |
ACB Technology Corporation
(Pittsburgh, PA)
|
Family
ID: |
26903374 |
Appl.
No.: |
07/208,659 |
Filed: |
July 28, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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129915 |
Oct 3, 1987 |
4762277 |
|
|
|
821806 |
Jan 23, 1986 |
|
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447000 |
Dec 6, 1982 |
4573637 |
|
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Current U.S.
Class: |
239/99; 137/509;
137/906; 239/533.15; 299/17; 137/312; 137/624.14; 251/355;
239/101 |
Current CPC
Class: |
B05B
1/323 (20130101); B26F 3/004 (20130101); B05B
1/083 (20130101); Y10S 137/906 (20130101); Y10T
137/86413 (20150401); Y10T 137/7835 (20150401); Y10T
137/5762 (20150401) |
Current International
Class: |
B05B
1/30 (20060101); B05B 1/32 (20060101); B26F
3/00 (20060101); B05B 001/08 () |
Field of
Search: |
;239/533.15,94,99,101,102.1 ;137/312,509,624.14,906 ;251/355
;299/17 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kashnikow; Andres
Assistant Examiner: Trainor; Christopher G.
Attorney, Agent or Firm: Parmelee, Miller, Welsh &
Kratz
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a divisional application of our commonly
assigned, copending application Ser. No. 129,915 filed Dec. 3, 1987
now U.S. Pat. No. 4,762,277; which was a continuation of
application Ser. No. 821,806 filed Jan. 23, 1986, abandoned, which
was in turn a continuation-in-part of application Ser. No. 447,000
filed Dec. 6, 1982, now U.S. Pat. No. 4,573,637 issued Mar. 4,
1986.
Claims
What is claimed is:
1. Apparatus for accelerating a slug of liquid comprising:
a housing forming a substantially rigid closed chamber suitable for
storing pressurized liquid at pressures greater than about 5,000
psi;
means for introducing liquid into the closed chamber under pressure
to compress liquid in the chamber and thereby store energy
primarily by liquid compression and mass in the closed chamber;
a nozzle connected to the housing and having a passage therethrough
with an inlet which communicates with the closed chamber formed by
the housing and an exit;
valve means for selectively sealing the nozzle passage relative to
the closed chamber and operative at liquid pressures greater than
about 5,000 psi from a closed to an open to a closed position to
release a slug of liquid driven from the closed chamber into the
nozzle passage by the energy stored in the compressed liquid, the
rate of opening of said valve means being sufficiently rapid that
the valve means is substantially fully opened in less time than is
required for the leading edge of the liquid slug to reach the
nozzle exit;
said valve means including means for biasing the valve means to the
closed position, and the biasing means providing a decreasing
biasing force as the valve means moves away from the closed
position to reduce the amount of energy stored in the biasing means
during opening of the valve means; and
means for breaking a vacuum in the nozzle passage after each slug
is released.
2. Apparatus for accelerating a slug of liquid comprising:
a housing forming a substantially rigid closed chamber suitable for
storing pressurized liquid at pressures greater than about 5,000
psi;
means for introducing liquid into the closed chamber under pressure
to compress liquid in the chamber and thereby store energy
primarily by liquid compression and mass in the closed chamber;
a nozzle connected to the housing and having a passage therethrough
with an inlet which communicates with the closed chamber formed by
the housing and an exit;
valve means for selectively sealing the nozzle passage relative to
the closed chamber and operative at liquid pressures greater than
about 5,000 psi from a closed to an open to a closed position to
release a slug of liquid driven from the closed chamber into the
nozzle passage by the energy stored in the compressed liquid, the
rate of opening of said valve means being sufficiently rapid that
the valve means is substantially fully opened in less time than is
required for the leasing edge of the liquid slug to reach the
nozzle exit;
the valve means including means which generates a force which
biases the valve means to the closed position and means upon which
the pressure of the compressed liquid in the closed chamber exerts
an opening force tending to drive the valve means to the open
position, said valve means repetitively opening when the opening
force generated by the compressed liquid exceeds the biasing force,
and closing when the release of liquid causes the opening force to
fall below the biasing force, such that a series of slugs of liquid
are released into said nozzle, and wherein the means includes a
valve member extending through the chamber of the housing and
having three coaxial first, second, and third portions of
increasing crosssectional areas, the first portion slidably fitting
in sealing relation inside the nozzle passage when the valve member
is in a closed position, the second portion seating against the
inlet end of the nozzle when the valve member is in the closed
position and the third position slidably extending through the
housing opposite the nozzle, the difference in cross-sectional
areas between said second and said third portions forming the means
against which the compressed liquid exerts the opening force to
drive said valve member toward an open position, and said first
portion being of such a length that, as the valve member is moved
toward the open position, said first portion continues to block the
release of liquid into the nozzle passage until the valve member
has accelerated to a speed which opens the nozzle passage at said
rapid rate as the first portion clears the nozzle passage; and
means for breaking a vacuum in the nozzle passage after each slug
is released.
3. The apparatus of claim 2 wherein said biasing means is connected
to the housing outside of the closed chamber and applies the
biasing force to the third portion of the valve member which
extends through said housing.
4. The apparatus of claim3 including means in addition to the
biasing means for decelerating the valve member as it reaches the
open position.
5. The apparatus of claim 4 wherein said decelerating means
includes means utilizing the liquid within the closed member to
decelerate the valve member.
6. The apparatus of claim 5 wherein said decelerating means
comprises a member defining a recess connected to the housing
inside the closed chamber and a plunger carried by the valve member
which projects into the recess as the valve member approaches the
open position to provide dampening as the liquid in the closed
chamber is forced out of the recess through a restrictive clearance
between the plunger and the walls of the recess.
7. The apparatus of claim 6 wherein said recess and plungers are so
shaped and dimensioned that as said plunger enters said recess,
said restrictive clearance between the plunger and walls of the
recess varies progressively to provide a deceleration force to the
valve member.
8. The apparatus of claim 7 including seal means coacting between
the housing and said third portion of the valve member which
extends through the housing and wherein said recess of the
deceleration means is an annular recess surrounding the seal and
said plunger is a cup-shaped member axially mounted on the valve
member, said cup-shaped member being provided with at least one
passage through the bottom thereof through which liquid can pass as
the cup-shaped member enters the annular recess to prevent trapped
liquid from being forced into the seal.
9. The apparatus of claim 2 wherein said nozzle is a cumulation
nozzle which further accelerates the forward portion of each slug
of liquid utilizing the kinetic energy of the slug.
10. The apparatus of claim 9 wherein said vacuum breaking means in
the cumulation nozzle breaks the vacuum after the forward portion
of each slug of liquid is accelerated.
11. The apparatus of claim 10 wherein said vacuum breaking means
comprises a passage extending axially through said valve member and
communicating both with the nozzle passage through the first
portion of the valve member and a source of a gas outside the
housing, said gas being at a pressure sufficient to break the
vacuum in the nozzle passage and empty substantially all liquid
from the nozzle passage before the next liquid slug is ejected into
the nozzle passage.
12. The apparatus of claim 2 including guide means axially mounted
on the first portion of the valve member and slidable within the
nozzle passage to maintain the valve member in alignment with the
nozzle passage when the first portion of the valve member is
withdrawn therefrom as the valve member is moved to the open
position.
13. Apparatus for accelerating a slug of liquid comprising:
a housing forming a substantially rigid closed member suitable for
storing pressurized liquid at pressures greater than about 5,000
psi;
means for introducing liquid into the closed chamber under pressure
to compress liquid in the chamber and thereby store energy
primarily by liquid compression and mass in the closed chamber;
a nozzle connected to the housing and having a passage therethrough
with an inlet which communicates with the closed chamber formed by
the housing and and exit;
valve means for selectively sealing the nozzle passage relative to
the closed chamber and operative at liquid pressures greater than
about 5,000 psi from a closed to an open to a closed position to
release a slug of liquid driven from the closed chamber into the
nozzle passage by the energy stored in the compressed liquid, the
rate of opening of said valve means being sufficiently rapid that
the valve means is substantially fully opened in less time than is
required for the leading edge of the liquid slug to reach the
nozzle exit;
means for biasing the valve means to the open and closed positions,
wherein the biasing means includes actuation means which generates
a force to move the valve means between the closed and open
positions and pressure sensing means responsive to the pressure of
the compressed liquid in the chamber to signal the actuation means
to open the valve means when the pressure reaches a selected value
and to again signal said actuation means to close the valve means
when the pressure of the compressed liquid in the chamber drops
below a selected value such that the valve means will repetitively
open and close to release a series of slugs of liquid into the
nozzle passage; and
means for breaking a vacuum in the nozzle passage after each slug
is released.
14. The apparatus of claim 13 wherein the actuation means includes
hydraulic cylinder and piston means mounted externally of the
closed chamber and having a piston rod operably connected to the
valve means for movement thereof.
15. The apparatus of claim 13 wherein the valve means includes a
center body within the chamber of the housing having an axial bore
formed therein, a valve member having three coaxial first, second,
and third portions, the first portion slidably fitting in sealing
relation inside the nozzle passage when the valve member is in a
closed position, the second portion seating against the inlet end
of the nozzle when the valve member is in the closed position and
the third portion slidably extending within the bore of the center
body wherein the cross-sectional area of said second portion is
greater than those of said first and third portions and the
cross-sectional area of said third portion is greater than that of
said first portion, the difference in cross-sectional areas between
said second and third portions forming the means against which the
compressed liquid exerts a seating force to maintain the valve
member in the closed position and the difference in cross-sectional
areas between said first and third portions forming the means
against which the compressed liquid exerts an opening force to
drive the valve member rapidly toward an open position, said first
portion being of such length that, as the valve member is moved
toward the open position, said first portion continues to block the
release of liquid into the nozzle passage until the valve member
has accelerated to a speed which opens the nozzle passage at said
rapid rate as the first portion clears the nozzle passage.
16. The apparatus of claim 15 wherein the biasing means includes
actuation means which generates a force sufficient to overcome said
seating force to move the valve means to said unseated position and
pressure sensing means responsive to the pressure of the compressed
liquid in the chamber to signal the actuation means to unseat the
valve means when said liquid pressure reaches a selected value,
said biasing means further including gas spring means which forces
the valve means to the closed position after each slug of liquid
has been ejected from the chamber.
17. The apparatus of claim 15 wherein said nozzle is a cumulation
nozzle which further accelerates that forward portion of each slug
of liquid utilizing the kinetic energy of the slug.
18. The apparatus of claim 17 including means in addition to the
gas spring means for decelerating the valve member as it reaches
the open position.
19. The apparatus of claim 8 wherein said deceleration means
includes means utilizing the liquid within the closed chamber to
decelerate the valve member.
20. The apparatus of claim 19 wherein said decelerating means
comprises a plunger carried by the valve member which projects into
a throat section of the bore of the center body as the vale member
approaches the open position to provide dampening as the liquid in
the closed chamber is forced out of the throat section through a
restrictive clearance between the plunger and the wall of the
throat section.
21. The apparatus of claim 18 including sealing means coacting
between the valve member and the bore of the center body to prevent
leakage of compressed gas and liquid therebetween.
22. The apparatus of claim 17 wherein said vacuum breaking means in
the cumulation nozzle after the forward portion of each slug of
liquid is accelerated.
23. The apparatus of claim 22 wherein said vacuum breaking means
comprises a passage extending through the cumulation nozzle
adjacent to the inlet thereof and communicating both with the
nozzle passage and as source of gas, said gas being at a pressure
sufficient to break the vacuum in the nozzle passage and empty
substantially all liquid from the nozzle passage before the next
liquid slug is ejected into the nozzle passage.
24. Apparatus for accelerating a slug of liquid comprising:
a housing forming a substantially rigid closed chamber suitable for
storing pressurized liquid at pressures greater than about 5,000
psi;
means for introducing liquid into the closed chamber under pressure
to compress liquid in the chamber and thereby store energy
primarily by liquid compression and mass in the closed chamber;
a nozzle connected to the housing and having a passage therethrough
with an inlet which communicates with the closed chamber formed by
the housing and an exit;
valve means for selectively sealing the nozzle passage relative to
the closed chamber and operative at liquid pressures greater than
about 5,000 psi from a closed to an open to a closed position to
release a slug of liquid driven from the closed chamber into the
nozzle passage by the energy stored in the compressed liquid, the
rate of opening of said valve means being sufficiently rapid that
the valve means is substantially fully opened in less time than is
required for the leading edge of the liquid slug to reach the
nozzle exit;
said valve means including a valve member which, in the closed
position of the valve means, seats against the nozzle inlet to
block the release of liquid through the passage and is provided
with an extension on the end thereof which slidably fits in sealing
relationship inside the nozzle passage, said extension being of
such a length that as the valve member is moved from the closed
position toward the open position, the extension continues
substantially to block the release of liquid through the nozzle
passage until the valve member has accelerated to a speed which
opens the passage at said rapid rate as the extension clears the
nozzle passage, and means for biasing the valve means to the closed
position and to an unseated position wherein said valve means is
moved from the nozzle inlet at preselected intervals and further
including means responsive to the pressure of the compressed liquid
in the chamber to exert a seating force on the valve means when
said valve means is in the closed position and to exert an opening
force to drive the valve means rapidly toward an open position
after said biasing means has unseated said valve means; and
means for breaking a vacuum in the nozzle passage after each slug
is released.
Description
BACKGROUND OF INVENTION
1. Field of the Invention
The present invention relates to an apparatus for accelerating
discrete volumes or slugs of liquid, and more particularly to
accelerating slugs of liquid through utilization of energy and mass
stored in compression of the liquid in a closed container.
2. Prior Art
There is a need for increased productivity in cutting and breaking
hard, strong substances such as rock, pavement and frozen earth.
One current method of achieving this end is the use of explosives,
usually placed in laboriously drilled holes and cavities. The
process is noisy, dangerous, and is a batch, as opposed to a
continuous, process that is typically slow and expensive. Another
method utilizes the mechanical impact breaker, typified by the
familiar jackhammer. Such devices are well developed and in
widespread use, but are heavy, punishing to the operator, and break
rock too slowly.
Yet another method of breaking and cutting hard, strong substances,
but one which is not yet in wide use, utilizes a pulsed liquid jet.
A pulsed liquid jet can briefly attain very high jet power for
moderate connected power, by storing energy over a time period that
is long compared to the jet duration. Such jets are well known to
the prior art and typically reach velocities of several thousand
feet per second and stagnation pressures of several hundred
thousand pounds per square inch. Experimental single-shot
laboratory results of several investigators have demonstrated the
effectiveness of such pulsed jets for breaking and cutting
difficult substances such as pavement and rock.
Pulsed jet devices preferably use a "cumulation" nozzle, such as
that disclosed, for instance, in U.S. Pat. No. 3,343,794 to
Voitsekhovsky, in which an energetic slug of liquid is supplied at
the entrance of a dry nozzle. The foremost portion of the water
slug is greatly accelerated as it travels along the contracting
passage, which concentrates most of the slug energy into the
kinetic energy of a small portion of the fluid slug. The resulting
transient liquid jet that exits from the nozzle has a peak
stagnation pressure many times higher than the static pressure that
occurs anywhere within the nozzle, which is of great practical
advantage. The internal shape of the nozzle has a profound effect
on the wall pressures that occur within the nozzle as is well known
in the prior art as demonstrated by U.S. Pat. No. 3,921,915.
The aforementioned experimental results were for the most part
obtained using single-shot laboratory apparatus. A successful
commercial apparatus must be capable of sustained production of
such pulsed liquid jets at a useful repetition rate under field
conditions. Most prior inventions utilizing cumulation nozzles have
energized the water slug by impact of a moving mass as disclosed
for example, in U.S. Pat. Nos. 3,343,794; 3,412,554; 3,905,552; and
3,921,915. In such devices, the pulse energy available to power the
liquid jet is the kinetic energy of the impacting mass which must
be accelerated by some means such as gravity, a propellant charge
or compressed gas. Means must also be provided to empty the nozzle,
replenish the liquid slug and maintain the shape and location of
the water slug in preparation for each pulse. Previous inventions
typically utilize an intermediary piston or diaphragm between the
liquid slug and impacting mass and a valve or diaphragm between the
liquid slug and the nozzle entrance. Such diaphragms must be
replaced before each pulse and the motion of a valve must be
closely synchronized with the impact of the moving mass. An
intermediary piston must provide for purging of air from the liquid
packet chamber. Material considerations, specifically allowable
stress, limit the mass impact velocity. Since kinetic energy is
proportional to the product of velocity squared and mass, large
values of pulse energy require a large moving mass. The result is a
heavy apparatus. In addition, the recoil impulse associated with
acceleration of a large mass to a high value of kinetic energy
results in a tool that is difficult to control. A proposed
alternate means of energizing the liquid is spark discharge as
disclosed in U.S. Pat. No. 3,647,137. However, this approach
requires the supply and rapid switching of large quantities of
electrical energy.
U.S. Pat. No. 3,883,075 suggests yet another method of producing a
liquid pulsed jet. Under this approach, a multichannel nozzle block
is rotated in front of an ejector supplied with a continuous flow
of pressurized liquid. In effect, the rotating nozzle block chops
the continuous liquid stream. Such devices are cumbersome and
require careful synchronization of the parts.
In general, the prior art liquid pulsed jet devices are handicapped
by excessive weight and mechanical complexity, low pulse energy, or
very low repetitive firing rate.
SUMMARY OF THE INVENTION
According to the present invention, discrete volumes or slugs of
liquid are accelerated to high velocities using energy stored by
compressing the liquid in a closed container. Liquid is introduced
under pressure into a container already filled with liquid to
compress it and thereby accumulate energy and mass in the
compressed liquid within the container. A slug of the liquid stored
in the container is then ejected from the container and accelerated
to a high velocity through conversion of the potential energy of
the compressed liquid into kinetic energy of the slug. By
repetitively introducing additional liquid into the container and
ejecting slugs of liquid, a series of pulsed liquid jets is
generated.
The apparatus according to the invention consists essentially of a
chamber and a nozzle, preferably a cumulation nozzle, separated by
a valve. The chamber, formed by a high-strength pressure vessel, is
charged with high-pressure compressed liquid by appropriate means
such as a pump or intensifier. The pulse energy and the pulse
volume (i.e. the slug of liquid that is ejected through the nozzle)
are stored in the slightly compressible working liquid contained in
the chamber. Some recoverable energy is also stored in elastic
deformation of the chamber walls. The required chamber pressure
depends on the volume of the chamber and the desired values of
pulse energy and pulse volume; for practical applications, the
required pressure may be as low as five thousand (5,000) pounds per
square inch and may be as high as about forty thousand (40,000)
pounds per square inch or even higher.
When the desired chamber pressure and energy storage have been
achieved, the valve is opened, allowing the pressurized liquid to
expel into the cumulation nozzle. The volume of liquid expelled,
i.e. the pulse volume or slug size, is a small fraction of the
chamber volume. The valve must be opened very rapidly to properly
utilize the cumulation nozzle. The valve must be substantially
fully opened in less time than is required for the leading edge of
the liquid slug to reach the nozzle exit. Rapid valve opening is
achieved in the preferred arrangement by providing on the end of
the valve member, an extension which lies in sealing relation
inside the nozzle passage. The length of the extension is such that
the valve member can accelerate to the required velocity by the
time that the extension, which initially blocks release of liquid
into the nozzle, clears the nozzle passage inlet. The preferred
means of actuating the valve is to utilize the rapid expansion
capability of the highly compressed liquid. This is achieved in a
preferred form of the invention by a valve member which seats
against the nozzle passage and extends across the pressure chamber
and through the housing on the opposite side or extends within a
bore of a center body of the chamber. The portion of the valve
member which passes through the housing or slides within the center
body bore is larger in cross-section than the portion which seats
against the nozzle passage such that the compressed liquid exerts
an opening force on the valve member. When the pressure of the
compressed liquid reaches a point where the opening force exceeds a
closing bias applied to the valve member, the valve opens to expel
liquid until the pressure drops sufficiently for the bias force to
reclose the valve. The valve motion is further controlled by means
of an energy dissipation device which serves to limit the valve
velocity to the desired maximum value and then slows the valve
gently to a stop so that the bias force may return the valve to the
closed position. With additional pressurized liquid supplied to the
chamber, this valve arrangement will automatically cycle to
repetitively produce pulsed liquid jets.
In another preferred form of the invention, the portion of the
valve member which passes through the housing or slides within the
bore of the center body is smaller in cross-section than the
portion which seats against the nozzle passage such that the
compressed liquid exerts a closing force on the valve member. A
hydraulic actuation device or other suitable means supplies an
unseating force to the valve member causing it to move from its
engaged position with the nozzle passage. Once the valve member is
unseated, it will very rapidly accelerate to an open position due
to the large opening force exerted by the pressurized liquid within
the housing by virtue of the fact that the extended portion of the
valve member within the nozzle passage has a diameter smaller than
the portion which passes through the housing or slides within the
center body. After a slug of liquid has been ejected into the
nozzle passage, the valve member is moved to the closed position by
a suitable hydraulic device or biased by a mechanical or compressed
gas spring into seated engagement with the nozzle passage, at which
point the liquid pressure within the chamber increases and holds
the valve member in the closed position until it is again opened by
application of the unseating force. Automatic or manual cycling is
achieved through the use of a transducer device or the like, which
senses and signals within a predetermined range of liquid pressures
in the chamber to control the opening and closing of the valve
member through known circuitry and control means.
The desired arrangement eliminates impact and the associated high
material stresses, and also avoids the weight penalty of a separate
energy storage means required in many of the prior art devices. It
is also simple, does not require precise synchronization of parts
as required in other pulsed liquid jet devices, and can reliably
generate high energy pulses at a high repetition rate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view through an apparatus incorporating
the present invention;
FIG. 2 is an enlarged view taken along line II--II of FIG. 1;
FIG. 3 is an enlarged view taken along line III--III of FIG. 1;
FIG. 4 is a partially fragmented, cross-sectional view of another
presently preferred embodiment of an apparatus incorporating
features of the present invention;
FIG. 5 is a partially fragmented, cross-sectional view of still
another embodiment incorporating the present invention;
FIG. 6 is a partially fragmented, cross-sectional view of yet
another apparatus incorporating the present invention;
FIG. 7 is an enlarged, partial cross-sectional view of a preferred
valve member and center body useful in an apparatus of the present
invention;
FIG. 8 is a partial fragmentary, cross-sectional view of another
preferred embodiment of the valve member and center body similar to
FIG. 7; and
FIG. 9 is a partially fragmented, cross-sectional view of another
embodiment of the present invention.
DETAILED DESCRIPTION
Referring now to the drawings, FIG. 1 illustrates the apparatus 1
of the present invention, usable for the repetitive production of
pulsed liquid jets. As illustrated, the apparatus comprises a high
strength pressure vessel in the form of a housing 3, which defines
a chamber 5, the housing 3 having an inlet 7 for introduction
thereto of a liquid. The housing 3 is illustrated as being
spherical, although it may be of other shapes as required to
facilitate fabrication or utilization of the apparatus. A line 9,
preferably a flexible hose, is connected to a means such as a pump
(not shown) for charging of liquid under pressure through inlet 7
into the chamber 5. The hose may be flexible or rigid, and there
may be provided an accumulator vessel (also not shown) at some
point therealong to control pressure fluctuations. A cumulation
nozzle 11, having a passage 13 therethrough which diminishes in
cross-sectional area toward an outlet 15, is secured to the housing
3, with the passage 13 communicating with chamber 5. The nozzle 11
may be formed as an integral part of the housing 3, or it may be
detachable as illustrated in FIG. 1. The nozzle 11, if detachable,
is securely mated to the housing 3 by any suitable means such as a
threaded connection or by other means, e.g. a bolted flange. A
seal, 12, should then be provided to prevent escape of pressurized
liquid at the juncture of the housing 3 and nozzle 11. A valve seat
17 surrounds the entry to passage 13, and the housing 3 has, in the
wall opposite the entry to passage 13, an opening 19.
A slidable valve member 21 is urged by a biasing device 23 into
sealing relationship with the valve seat 17 to seal the passage 13
of the nozzle 11 from the chamber 5. The valve member 21 extends
through the chamber 5 and has first, second and third portions of
increasing cross-sectional area. The first portion 25 of the valve
member 21 is slidable in close fitting sealing relation within the
inlet portion 27 of the passage 13 of nozzle 11 and is provided on
the end 29 thereof with guide vanes 31, for example, three as
shown, which are slidable along the walls of passage 13. As best
seen in FIG. 2, channels 33 are formed by the guide vanes 31
through which liquid can be expelled from the chamber 5 into the
nozzle passage 13 when the valve member 21 is operated to the open
position.
The second portion 35 of the valve member 21 has a shoulder 37
which mates with the valve seat 17, while the third portion 39 of
the valve member 21 extends through opening 19 in the wall of
housing 3. The first portion 25, second portion 35, and third
portion 39 are of increasing cross-sectional area, as shown in the
drawing, where D1 is smaller than D2 which is smaller than D3.
The biasing means 23, which is preferably contained in a cap 41
affixed to the housing 3, for instance, by means of bolts 43 and
nuts 45, applies a biasing force to the slidable valve member 21.
The biasing means maintains the shoulder 37 of the second portion
35 of the slidable valve member 21 in sealing relationship with the
valve seat 17. As illustrated, the biasing means 23 provides for a
decreasing biasing force to be exerted as the slidable valve member
21 moves away from the valve seat 17. The illustrated biasing means
23 comprises a spring 47 and two pairs of pivotally connected arms.
Arms 49 of the first pair are pivotally attached by pins 51 to
mounts 53 on the housing 3 and are connected together at their free
ends by the tension spring 47 hooked through holes 55 in the arms.
The arms 61 of the second pair are each pivotally connected at one
end by a common pin 57 to an extension 59 on valve member 21 and at
the other end to one of the arms 49 by a pivot pin 63. Since the
bias means applies a decreasing force as the valve member
approaches the open position, less energy is stored by this
mechanism which permits more rapid acceleration of the valve member
during valve opening and softer impact of the valve member during
closing.
The third portion 39 of valve member 21, as discussed extends
through the opening 19 in the housing which is provided with
annular seal 65 to prevent leakage of compressed liquid from
chamber 5 as the portion 39 slides in and out in opening 19. The
seal 65 is held in place by a block 67 having a flange 69 that is
secured to the housing 3 by securing means such as bolts 71.
As will be described in more detail below, the valve member 21 is
opened rapidly to release a slug of liquid from the chamber 5. In
order to stop the rapidly moving valve member 21 and absorb its
kinetic energy as it approaches the full open position, energy
absorbing decelerating means are provided. The device provided
utilizes the liquid in the chamber 5 for hydraulic dampening. A
cup-shaped member 73 is coaxially mounted on the second portion 35
of the valve member 21 with the generally annular flange 75 thereof
extending in spaced relation around the third portion 39 of the
valve member. This annular flange 75 forms a plunger which is
received in an annular recess 79 in housing 3 surrounding opening
19 and spaced therefrom by a shoulder 81, as the valve member 21
approaches the full open position. The outer wall 83 of annular
recess 79 extends outwardly at an obtuse angle .alpha. from the
base 85 of the recess, while the outer surface of annular flange 75
tapers inwardly at the same angle. Apertures 77 extend through the
cup-shaped member 73 to connect the bottom of the annular space 87
formed between the flange 75 and the portion 39 of the valve member
21 with the chamber 5.
Vacuum breaker means for the nozzle passage 13 is provided in the
form of passage 89 extending axially through the valve member 21.
The end of the passage 89 in portion 39 of the valve member 21 may
be open to the atmosphere as shown to allow the remaining liquid to
flow out of the nozzle passage 13 through its own momentum and/or
gravity. Alternatively, a vacuum could be applied to passage 89
although this would present the danger of sucking debris into the
nozzle in some applications. Preferably, passage 89 is connected to
a source of positive gas pressure (not shown) to expel
substantially all remaining liquid from the nozzle passage 13
between pulses.
In the operation of the present invention, the hose 9 is connected
to a source of liquid, under pressure, with the valve member 21 in
the closed position shown in FIG. 1, sealing off passage 13 of the
nozzle 11. As additional liquid is charged to the chamber, the
liquid, such as water, will be compressed and the pressure in the
chamber will increase so that energy and liquid mass are stored.
When the force exerted by the pressurized liquid in the chamber 5
on the valve member 21 due to the greater cross-sectional area of
the portion 39 relative to the portion 35 exceeds the force exerted
by biasing means 23, the valve member 21 will begin to move toward
the open position unseating the second portion 35 from the valve
seat 17. Since the first portion 25 of the valve member 21 is
closely fit in slidable sealing relation within the inlet portion
27 of the nozzle passage 13, almost no fluid excapes from the
chamber at this point. However, since the shoulder 37 formed by the
difference in diameters between the portions 35 and 25 is now
exposed to the pressurized liquid in chamber 5 to increase the
opening force, the valve member 21 is further accelerated toward
the open position. In addition, as discussed above, the bias means
shown exerts a decreasing bias force as the valve opens to reduce
opposition to the opening forces and permit additional acceleration
of the valve member 21.
The length of the first portion 25 of the valve member 21, which
continues to block the flow of liquid into the nozzle passage 13,
is selected such that the valve member reaches sufficient velocity
by the time that the end 29 of portion 25 clears the nozzle passage
inlet that the valve is substantially fully opened in less time
than is required for the leading edge of the liquid slug to reach
the nozzle exit 15. The valve is fully opened when the
cross-sectional area of the valve opening substantially equals that
of the nozzle passage inlet 27. This is important to proper
operation of the cumulation nozzle and effects efficient conversion
of potential energy stored in the compressed liquid in chamber 5
into kinetic energy of the slugs of liquid injected into the
cumulation nozzle 11. The guide vanes 31 remain inside the nozzle
passage 13 throughout the full travel of the valve member 21 to
maintain alignment of the parts.
The valve member 21 gains considerable kinetic energy in
accelerating to the velocity required for rapid injection of liquid
into the nozzle 11. In order to stop the valve member 21
preparatory to closing the valve, this energy must be absorbed in a
short distance while a considerable opening force is still being
applied to the valve member by the liquid in chamber 5. As the
valve member 21 approaches the full open position, the flange 75 on
cup-shaped member 73 begins to enter the annular recess 79. Liquid
in the recess 79 is forced out through the clearance between the
flange 75 and the outer wall 83 of the recess to generate a force
which retards the opening movement of the valve member 21. The
taper of the outer wall 83 of the recess 79 and the outer surface
of flange 75 narrows the clearance between the flange and recess as
the flange enters the recess thereby maintaining a large
deceleration force as the velocity of the valve member 21
decreases. Liquid trapped in the annular space 87 inside the
cup-shaped member 73 escapes through the apertures 77 to prevent
forcing the trapped liquid beyond the seal 65.
Ejection of liquid into the passage 13 of nozzle 11 causes the
chamber pressure, and thus the opening force exerted on valve
member 21, to decrease. When this opening force falls below the
closing force generated by the biasing means 23, the valve member
21 moves to the closed position with the first portion 25 in
sealing relation inside nozzle 13 and with the shoulder 37 seated
against seat 17 thereby enabling repressurization of the liquid in
chamber 5 for a repeat cycle. So long as pressurized fluid is
supplied through line 9, the cycle will be automatically repeated
to generate a continuous series of pulsed liquid jets. The rate at
which pressurized liquid is delivered to the chamber 5 by line 9
determines the rate at which the valve cycles. In this manner, the
apparatus stores energy over a period of time and releases it at
spaced intervals as kinetic energy of slugs of liquid. Thus, the
device can produce a high energy pulsed liquid jet with moderate
connected power.
As is well known, the cumulation nozzle accelerates the leading
edge of the slug of liquid injected into the nozzle passage 13 by
concentrating the kinetic energy of the slug in the forward
portion. This can result in the trapping of some low energy liquid
in the nozzle passage 13 by the vacuum created behind the trapped
liquid when the valve member 21 is returned to the closed position.
Such trapped liquid must be removed from the nozzle 11 before the
next pulse. Passage 89 breaks the vacuum or admits pressurized gas
or air so that the nozzle passage 13 is essentially free of liquid
by the time the next slug is ejected into the nozzle.
Additional embodiments of apparatus incorporating the present
invention are depicted in FIGS. 4-9, in which similar mechanical
elements corresponding with those previously described in FIG. 1
are designated by "primed" numbers. The device depicted in FIG. 4
is suitable for manual, automatic or semiautomatic operation due to
the configuration of valve member 21' employed therein. Contrary to
the construction of the previously described embodiment of FIGS.
1-3, the diameter of second portion 35' of the valve member 21' is
greater than the diameter of its third portion 39'. Thus
pressurized liquid within the closed chamber 5' urges the shoulder
37' of the valve member 21' into sealing engagement against the
valve seat 17' to close-off the passage 13' of the nozzle 11'. The
diameter of the first portion 25' of the valve member 21' is
smaller than the diameter of the third portion 39'. As will be
explained hereinafter, when an unseating force is applied to the
valve member 21', the shoulder 37' is moved away from sealing
relation with the valve seat 17', whereby the pressurized liquid in
the chamber 5' exerts an opening force on the valve member 21',
tending to accelerate the valve member 21' toward the open
position.
The valve member 21' does not extend through an opening in the
housing 3' as in the device of FIG. 1, but rather is slidably
fitted within the cylindrically shaped center body 20. Center body
20 is located at a side of the housing 3' opposite the valve seat
17' and extends into the interior of chamber 5'. This arrangement
facilitates reduction of the length and mass of the valve member
21'. The center body 20 of FIG. 4 is comprised of a cylinder 22
having a central bore 24 formed therein which slidably receives the
third portion 39' of the valve member 21' therein. The rear of
cylinder 22 is secured within the end block 67', which in-turn is
threadably secured to the housing 3'. A stationary ring seal 65' is
fitted between the block 67' and housing 3' to prevent leakage of
compressed liquid from the chamber 5' and the adjacent liquid inlet
7'. A pressurized source of liquid is fed from a hose or pipe 9' to
a passage 10 formed within the end block 67' which communicates
with the inlet 7'. A second stationary ring seal 68 is seated
between the end block 67' and the cylinder 22 to prevent liquid
leakage therebetween. A cylindrical skirt 26 is secured around the
cylinder 22 and extends outwardly therefrom to receive an enlarged
plunger section 28 of the valve member 21' therein which serves to
decelerate the valve member during the opening thereof. As the
valve member 21' approaches the open position, the plunger 28
enters the throat of the cylindrical skirt 26 and traps liquid
therein which exerts a deceleration force on the member 21'. The
bore of the cylindrical skirt 26 may be tapered or otherwise
contoured so that the peripheral radial clearance formed with the
plunger 28 varies as the plunger 28 moves into and within the
cylindrical skirt 26, yielding a deceleration force that varies
with the position and velocity of the valve member 21' in an
optimal manner. The third portion 39' of the valve member 21'
contains one or more spaced-apart, circumferential grooves into
which are fitted one or more ring-shaped seals 30 which slidably
and sealably engage the bore 24 of the center body 20 to prevent
leakage of pressurized liquid from the chamber 5' along the
interface between the valve member 21' and the bore 24 of the
center body.
In order to open the valve member 21', which is normally held in
the closed position by the force of the pressurized liquid in the
chamber 5', a hydraulic actuation device 40 of known type is
provided, secured to the end block 67' by way of bolts 43'.
Slidably fitted within th hydraulic actuation means 40 is a hollow
cylindrical piston 47 provided with slidable seals 45. A rod 44 is
attached by a threaded connection or other suitable means to the
end 94 of the third portion 39' of the valve member 21'. The rod 44
is provided with a larger diameter end portion 42 which is adapted
to engage the end of the hollow cylindrical piston 47. The
hydraulic actuation means 40 also includes a fluid orifice 46 for
the introduction and exhausting of hydraulic fluid. Pressurized air
or gas, introduced through orifice 48, acts on the end 94 of the
third portion 39' of the valve member 21', providing a bias force
that tends to exert a closing force on the valve 21'. A pressure
sensing means, such as a known transducer device 50, is mounted
within the walls of the housing 3' (shown) or along the supply line
9' with its sensing end communicating with the liquid within the
chamber 5'. When the liquid pressure within the closed chamber 5'
reaches a predetermined level by way of liquid flow through inlet
7', the transducer device 50 transmits a signal through
appropriate, known circuitry and control means (not shown) to
activate the hydraulic actuation means 40, by supplying hydraulic
fluid under pressure into orifice 46 and thereby causing the
cylinder 47 to exert an unseating force on the enlarged portion 42
of the rod 44, and thus causing the shoulder 37' of the valve
member 21' to be pulled away from sealing engagement with valve
seat 17'. Since the first portion 25' of the valve member 21' is of
a smaller diameter than the third portion 39', the pressurized
compressed liquid contained within chamber 5' exerts an opening
force on the valve member 21', accelerating the valve member 21'
toward the open position. The enlarged portion 42 attached to the
rod 44 accelerates away from the cylindrical piston 47, so that
said piston 47 is not required to duplicate the rapid motion of the
valve member 21'. A liquid slug is ejected from the chamber 5' into
the nozzle 13' when the first section 25' of the valve member 21'
no longer blocks the inlet to the nozzle passage 13'. Ejection of a
slug of liquid into the passage 13' of the cumulation nozzle 11'
causes the pressure within chamber 5' to decrease. When the liquid
pressure, sensed by the transducer device 50, falls below a
specified level within the chamber 5', the control means ceases to
supply hydraulic fluid under pressure to orifice 46. A coil spring
49 then returns the cylindrical piston 47 to its original position.
The valve member 21' is decelerated gently to a stop by the action
of the plunger section 28 moving within the cylindrical skirt 26
and also by the action of the bias force exerted on the end 94 of
the valve member 21' by the compressed gas introduced through
orifice 48. The bias force then moves the valve member 21' forward
into sealing engagement with the valve seat 17' of the nozzle 11'.
Liquid is replenished within the chamber 5' by way of inlet 7'. The
repetitive cycle continues as the pressure sensing device 50
detects an increase in liquid pressure and causes the opening of
the valve 21' by actuation of the hydraulic device 40. Other
methods of separating the shoulder 37' of the valve 21' from the
valve seat 17', in lieu of hydraulic actuation device 40, such as
levers, cams, solenoid actuators, etc., will be obvious to one
skilled in the art and are deemed to be included herein.
The cumulation nozzle 11' of the device depicted in FIG. 4 is shown
as a two-piece detachable design. A locking collar 32 is threadably
connected to the housing 3' and secures the nozzle base element 34
thereto. The detachable nozzle 11' is then threadably secured to
the base element 34. In this manner, nozzle 11' is easily removed
for inspection, maintenance or for compact transport of the
apparatus 1. An air or gas passage 36 formed through the locking
collar 32 communicates with a second passage 38 formed through the
base element 34 to communicate with the nozzle passage 13'.
Passages 36 and 38 provide a means for the introduction of a
pressurized gas such as air or nitrogen within the nozzle passage
to break the vacuum therein and clear liquid from the passage 13'
after each slug is ejected into the nozzle, as previously
described.
Another presently preferred embodiment or our invention is
illustrated in FIG. 5. The apparatus 1 of FIG. 5 is similar, in
most details of construction, to those previously described in
FIGS. 1 or 4. In this device a compressed fluid biasing means 60,
preferably in the form of a compressed gas spring, is employed in
place of the previously described mechanical spring device 23 of
FIG. 1. In FIG. 5, a slidable valve member 52 is urged by the
biasing means 60 into sealing relationship with the valve seat 17'
to close-off the passage 13' of the cumulation nozzle 11' from the
chamber 5'. The valve member 52 extends within the chamber 5' and,
like the device of FIG. 1, has first, second and third portions of
increasing cross-sectional area. The first portion 54 of the valve
member 52 is slidable in close fitting, sealing relationship within
the inlet portion 27' of the passage 13' of the nozzle. The end of
the valve member 52 has a tapered nose 29'. In this embodiment,
there is no need for the guide vanes 31 of FIG. 1, because the
tapered nose 29' adequately centers the valve member during its
closing stroke by virtue of the fact that valve member 52 is
slidably guided within the bore 24' of the center body 20.
The second portion 56 of the valve member 52 has a shoulder 56'
which mates with the valve seat 17' to seal-off the nozzle passage
13' when the valve member 52 is in the closed position. The third
portion 58 of the valve member 52 slidably extends through the bore
24' of the center body 20. The rearward end 94 of the third portion
58 of the valve member 52 faces an enclosed storage chamber 62
which contains the compressed fluid of the biasing means 60. As in
the previously described embodiment of FIG. 1, the first portion
54, second portion 56 and third portion 58 are of increasing
cross-sectional area. An end block 70 is threadably attached to the
housing 3' and forms the cylindrical bore 24' of the center body
20. A stationary seal 88 is positioned between the end block 70 and
the housing 3' to prevent pressurized liquid from leaking
therebetween. A conduit 9' is connected to a source of pressurized
liquid, which enters the closed chamber 5' by way of passageway 10
in end block 70 and then by way of an annular passageway forming
inlet 7', surrounding the center body 20 adjacent to the sidewalls
of the housing 3'. A tube-like member 72 carrying a flange 74 is
attached by way of bolts 76 to the end block 70 of the housing.
Member 72 contains an internal cavity which forms the storage
chamber 62 for retaining the compressed fluid such as, for example,
compressed gaseous nitrogen. Member 72 also contains a valve member
62' to permit periodic introduction of compressed fluid for
resupply to the storage chamber 62 in order to maintain proper
pressure therein.
The valve member 52 also has a enlarged diameter plunger section
28' which projects into the throat section 26' of the center body
as the valve member approaches the open position. The plunger 28'
provides a deceleration force on the valve member 52 as the liquid
trapped within the throat section 26' is forced out of the throat
section 26' through a restrictive peripheral clearance between the
plunger 28' and the bore of the member 26'. The third portion 58 of
the valve member 52 is provided with liquid sealing means 80 and
fluid sealing means 84. The liquid sealing means 80 comprises one
or a plurality of spaced-apart seals 82 fitted within
circumferential grooves formed in the valve member 52. Likewise,
the compressed fluid sal means 84 comprises one or a plurality of
seals 86 fitted within circumferential grooves formed at the end of
the third portion 58 of the valve member 52. The liquid sealing
means 80 slidably coacts between the valve member 52 and the bore
24' of the center body 20 to prevent the leakage of compressed
liquid therethrough. The fluid seal means 84 slibably coacts
between the valve member 52 and the bore of the storage chamber 62
to prevent compressed gas leakage therebetween. Hence, the sealing
means 80 and 84 provide a sealed-off area 90 therebetween which is
both liquid and gas-free. A vent passage 92 is formed between the
innerfaces of the end block 70 and the flange 74, communicating at
its outer end with the atmosphere and at its inner end with the
sealed-off area 90 at the center bore 24' of the center body 20. In
the event of a failure in either of the liquid sealing means 80 or
the compressed fluid sealing means 84, leaking liquid of fluid
would exhaust into the sealed-off area 90 and escape through the
vent passage 92. Such leakage is readily detectable by the operator
so as to permit appropriate maintenance in order to restore the
working efficiency of the device. This arrangement is also a safety
feature in that, in the event of a failure of the liquid sealing
means 80, the vent passage 92 provides pressure relief for the
cavity 90 and thus avoids the possibility that high pressure water
might invade the gas spring storage chamber 62.
In operation, the compressed gas within the fluid chamber 62 is at
a sufficiently high pressure to forcibly bias the end 94 of the
third portion 58 of the valve member 52 toward the nozzle, forcing
valve surface 56' into sealing engagement with the valve seat 17'.
As liquid, such as water, is introduced into the chamber 5' through
the conduit 10 and inlet 7', the liquid within the chamber 5' is
compressed and the pressure in the chamber increases. When the
opening force exerted by the pressurized liquid in the chamber 5'
on the valve member 52 exceeds the biasing force exerted by the
pressurized gas within storage chamber 62, the valve member 52 will
begin to move toward the open position, unseating the shoulder 56'
of the second portion 56 from the valve seat 17'. After the first
portion 54 clears the valve seat 17' the slug of liquid is ejected
from the chamber 5' into the nozzle passage 13'. Ejection of liquid
into the passage 13' causes the pressure within chamber 5', and,
thus, the opening force exerted on valve member 52, to decrease.
When this opening force falls below the closing force generated by
the gas spring biasing means 60, the valve member 52 moves into the
closed position as previously described. As the valve member 52
moves toward the closed position, it displaces liquid from the
chamber 5', which serves to limit the closing speed of the valve
member and thus avoid damaging impact of the shoulder 56' on the
valve seat 17'. The cycle will automatically repeat to generate a
continuous series of pulsed liquid jets so long as pressurized
liquid is delivered to the chamber 5.
A vacuum breaker for the device of FIG. 5 is provided in a collar
96, fitted around the nozzle 11' and threadably attached to the
locking collar 32'. Collar 96 carries a gas-tight seal ring 100 at
its outer edge, held within a grooved flange around the inner
periphery thereof. The collar 96 also has an inlet port 98 to which
a source of pressurized gas (preferably air, for economic reasons)
is attached. The inlet port 98 communicates with an air passage 102
formed between the collar 96 and the outer periphery of the nozzle
11'. Passage 102 communicates with a passage 38' formed within the
base element 34'. The inner end of the air passage 38' communicates
with the passage 13' of the nozzle. Pressurized gas flows from its
source through the inlet port 98 to passages 102 and 38' and thence
to the nozzle passage 13' to clear the nozzle passage 13' of liquid
after each pulse.
The device is suitable for use in hand held operations involving
the cutting of rock, concrete or other materials. In this regard,
the apparatus 1 is fitted with a handle 78 which is rigidly
attached to the member 72. The handle 78 may also be fitted with
conventional actuation switches or liquid flow control levers (not
shown) to control the operation of the device. Larger variations of
the device, too large and heavy for hand held use, would be
provided with suitable means to attach the device to appropriate
handling equipment.
Another presently preferred embodiment of the apparatus of 1 of the
present invention is depicted in FIG. 6, in which the center body
20' is of a one-piece construction. A valve member 104 is slidably
positioned within the bore 102 of the center body 20' and is urged
by the compressed fluid biasing means in the form of a gas spring
60' into sealing engagement with the valve seat 17', thus
closing-off the passage 13' of the nozzle 11' from the chamber 5'.
The valve member 104 has first, second and third portions of
increasing cross-sectional area, similar to the valve members 21
and 52 depicted in FIGS. 1 and 5, respectively. The first portion
106 of the valve member 104 is slidable in close fitting, sealing
relation of the inlet portion 27' of the nozzle passage 13'. The
second portion 108 of the valve member 104 has a tapered shoulder
which mates with the valve seat 17', while the third portion 110
slidably fits within the bore 102 of the center body 20'. The
biasing means 60' is a compressed gas such as nitrogen, introduced
through a valve member 62' into the gas storage chamber 112 which
is formed within the center body 20'. As in the embodiment of FIG.
5, the apparatus depicted in FIG. 6 includes a valve member 104
which contains fluid sealing means 84' and liquid sealing means
80'. Both of the sealing means 84' and 80' are comprised of one or
more seals fitted within grooves formed circumferentially in the
valve member 104 for movement therewith along the bore 102 of the
center body 20'. The seal means 84' prevents leakage of the
compressed fluid, such as nitrogen, of the biasing means 60' into
the sealed-off area 90'. The liquid sealing means 80' prevents
leakage of compressed liquid, such as water, within chamber 5'
rearwardly to the sealed-off area 90'. A vent passage 114 is formed
within the center body 20' and communicates at one end with the
sealed-off area 90', between the points of travel of the sealing
means 84' and 80'. The other end of the vent passage 114 may be in
direct communication with the atmosphere or it may be lightly
plugged. In the latter case, if a leak should occur in either of
the sealing means 80' and 84', the resultant pressure surge within
the vent passage 114 would cause the plug to pop from its seat so
as to alert the operator as to a potential problem with the seals.
The one-piece center body 20' is secured within a central bore of
the end block member 70' which, in turn, is threadably secured to
the rear of the housing 3'. Also, as previously described,
stationary sealing rings 88' and 116 are provided between end block
70' and the housing 3' and between the center body 20' and housing
end block 70', respectively, in order to prevent leakage of the
compressed liquid from the chamber 5'. As in the previously
described embodiments, a source of pressurized liquid, such as
water, for example, is connected to the apparatus 1 by way of a
conduit 9' which enters the enclosed chamber 5' by way of a
passageway 10 formed within the end block 70' to the annular inlet
7' of the housing.
The valve member 104 also contains a flared plunger section 118
which has a diameter slightly smaller than the diameter of the
throat 120 of the center body 20'. The plunger 118 acts as a energy
absorbing, decelerating means which utilizes the liquid in the
throat area 120 for hydraulic dampening in order to assist in
stopping the rapidly moving valve member 104 and to absorb its
kinetic energy a sit approaches the full open position. The
apparatus 1 of FIG. 6 also includes a vacuum-breaking means on the
nozzle 11', similar to that previously described in the embodiment
of FIG. 5. The apparatus likewise can be provided with a handle 78
as shown to permit hand-held operation thereof at the work site, or
other suitable means to permit attachment to handling
equipment.
In the embodiment depicted in FIG. 1, the liquid seal 65 between
the housing 3 and the valve member 21 is stationary while those
depicted in FIG. 4 through 6 are moveable with the sliding valve
member. Additional arrangements of the various seals are shown in
FIGS. 7 and 8, wherein the liquid sealing means 122 is stationary
and affixed to the center body 20' while the compressed fluid
sealing means 124 is carried by the moveable valve member. The
configuration of the center body 20' shown in FIG. 7 is suitable
for use in the apparatus of FIG. 6 and would function in the manner
previously described, although the sealing arrangement with the
valve member is slightly modified. Positioned adjacent to the
enlarged throat portion 120' of the bore 102 of the center body 20'
is the liquid sealing means 122. The sealing means 122 is made up
of one or more seal rings 130. The seals 130 are held securely in
place by a threaded locking ring 132 adjacent to the throat 120' of
the center of the body 20', where the seals 130 are compressively
held in sealing engagement against the sliding valve member 126.
The fluid sealing means 124 is comprised of one or more ring seals
134 which are carried by the valve member 126 within
circumferential grooves formed at its rearward end. In order to
decrease the mass of the rapidly moving valve member 126, a portion
of the interior thereof is removed to form a hollow cavity 136
therein. This not only yields a lighter device but also provides
for improved dampening and deceleration of the valve member 126 due
to the decreased mass. A vent passage 114 is also provided in the
center body 20' communicating with the sealed-off area 90' of the
bore 102 and functions in the manner previously described, in the
unlikely event leaks should occur in the sealing means 122 and
124.
The embodiment of valve member 128 shown in FIG. 8 provides a
unique vacuum breaking means for directly injecting a compressed
gas into the nozzle passage 13'. A passage 140 is formed within the
valve member 128 having one end in communication with the
sealed-off area 90' and the other end in communication with the
passage 13' of the nozzle 11' when the valve member 128 is in the
closed position depicted in the drawing. Hence, pressurized gas
from a source attached to an external orifice 138 flows through the
passage 114 to the sealed-off area 90' of the bore 102 of the
center body and, thence, flows to the passage 140 whereupon it
enters the nozzle passage 13' to expel liquid which may remain
therein after a slug has been ejected. In order to prevent high
pressure liquid within the chamber 5' from entering the passage 140
while the valve member moves to the open position, the outlet end
of the passage 140 is fitted with a one-way check valve 142. The
pressurized liquid in chamber 5' causes the one-way check valve 142
to close-off the passage 140 when the valve member 128 moves from
the closed to the open position. Pressurized gas flowing in the
opposite direction within the passage 140 is at a much lower
pressure than the liquid within chamber 5' and, hence, will not
cause an opening of the one-way valve 142 until the valve member
128 is in the closed position shown in FIG. 8.
The unique vacuum breaking means of FIG. 8 also permits the
introduction of a lubricant into the cavity 90' to provide for the
lubrication of the seal elements in the liquid and fluid sealing
means 122 and 124. Since there is a tight fit between the sliding
seals 134 and the bore 102, as well as between the stationary seals
130 and the sliding valve member 128, it is sometime advantageous
to supply a lubricant at the interface between these sealing
elements so as to decrease frictional wear and thus increase the
life of these elements. Lubricant, admixed with the vacuum breaking
gas, flows through the orifice 138 into the vent passage 114 and,
thence, into the sealed-off area 90' of the bore 102. The opening
and closing action of the valve member 128 distributes the
lubricant along the sidewall of the bore 102 to provide contact
with the sealing elements 130 and 134.
The embodiments of FIGS. 7 and 8 also include a pressurized fluid
biasing means 60' in the form of a gas spring which exerts a
closing force on the respective valve members 126 and 128. The
valve member 128 of FIG. 8 also preferably contains a hollow
interior portion 136' in order to reduce the mass thereof. The
valve members 126 and 128 also each carry an enlarged plunger
section 118' which acts as a decelerating means through the
hydraulic action of the liquid trapped within the throat section
120' of the bore 102 when the valve member moves to the open
position.
There are other alternative constructions for the housing 3 which
would be apparent to those skilled in the art in light of the
description of the invention contained herein. One such
modification would be to cast the spherical housing in two pieces,
in the form of hemispheres. One of these hemispheres could be cast
with an integral cylindrical portion forming the center body
thereof with the passage ways for venting and introduction of
pressurized fluid being directly formed by way of casting or by
subsequent drilling and machining operations. These hemispheres,
after machining, could then be joined by welding, bolting, or the
like.
A further preferred construction of the housing is shown in FIG. 9
wherein a spherical housing 3" is cast as a single piece, with an
integral center body 20" cast within chamber 5" thereof. The
housing has a bore 148 at the nozzle end thereof to permit core
placement and removal in a conventional casting operation. The
center body 20" has a cylindrical bore 150 therein preferably
formed during the casting operation. A liquid inlet passage 144 is
also cast or drilled within the wall of the housing 3", having one
end in communication with the chamber 5". The other end of the
passage 144, at the rear face of the housing 3", is closed-off with
a metal plug 146. A liquid orifice 143 is formed within the housing
3" in communication with the inlet passage 144 to permit the supply
of pressurized liquid, preferably water, to the chamber 5", as
previously described. The nozzle assembly, employing the base
element 34' and locking collar 32' are also similar to those
described above.
A cylindrically shaped wear sleeve 152 is press fitted within the
bore 150 of the center body 20" and has an inside bore 155 of
constant diameter for slidably receiving the valve member 145
herein. The wear sleeve, formed of a wear and corrosion resistant
material, can be replaced to extend the useful life of the
apparatus. A passage 158 is formed through the wear sleeve 152 near
the rearward end thereof communicating with the pressurized fluid
supply orifice 160 and the pressurized fluid storage area 160' of
the fluid biasing means. Pressurized fluid, such as gaseous
nitrogen, is injected into the storage chamber 160' by way of the
supply orifice 160 and the passage 158 to apply the previously
described gas spring biasing force to the valve member 145 to
close-off the seat 17' of the nozzle passage 13'.
The valve member 145 shown in FIG. 9 functions in a similar manner
to the valve member of FIG. 8. The liquid sealing means 80' and the
fluid sealing means 84' are carried by the valve means 145 and
together these sealing means define a liquid and fluid free,
sealed-off area 90' therebetween. The liquid and fluid sealing
means 80' and 84', respectively, comprise one more seal elements
with bore rider rings secured adjacent thereto to prevent the valve
member from contacting and scoring the bore 155. In this manner,
liquid and fluid leakage between the seal elements and the bore is
prevented.
The valve member 145 also has a vacuum breaker passage 140' formed
therein communicating at one end with the nozzle passage 13' when
the valve member 145 is in the closed position shown in FIG. 9. The
other end of the passage 140' is in communication with the seal-off
area 90' of the bore 155' to receive pressurized gas, such as air
or nitrogen, or the like, to clear the nozzle passage 13' of liquid
after each pulse, in the manner previously described. A one-way
check valve 142' is also provided within passage 140' to prevent
back-flow of high pressure liquid from chamber 5" into the passage
140'. In order to supply the required pressurized gas to the
passage 140', the wear sleeve 152 has a reduced diameter portion
154 around its outer circumference which forms an annular passage
156 between the outer wall of the wear sleeve 152 and the bore 150
of the center body 20". An orifice 164 connected to a source of
pressurized air or nitrogen or the like is formed in the housing 3"
and communicates with the annular passage 156. One or more holes
166 are formed through the wear sleeve 152 communicating with the
annular passage 156 at one end, and the sealed-off area 90' at the
other end. In this manner, pressurized gas flow is established
between the orifice 164 and the passage 140' of the valve member
145 to insure that the nozzle passage 13' is cleared of liquid
after each slug is ejected. A source of lubricant may also be
introduced into the pressurized gas supplied through the orifice
164 to provide the sealing means 80' and 84' with a supply of
lubricant in the manner previously described.
In order to prevent fluid leakage from the storage area 160' of the
gas spring into the annular passage 156, a ring seal 162 is
provided around the wear sleeve 152 to coact with the bore 150 of
the center bore between the communication points of the gas
orifices 160 and 164. The seal 162 segregates the respective gas
flows from orifices 160 and 164 to prevent an unwanted pressure
drop in the storage area 160' of the biasing means. The seal 162 is
held in place by a pair of spaced-apart, raised ribs 168 formed on
portion 154 of the wear sleeve 152. The ribs 168 have a diameter
nearly equal to that of the bore 150 of the center body 20". Hence,
the ribs 168 also function as a means for centering the reduced
diameter portion 154 within the bore 150 to provide uniform spacing
for the annular passage 156 existing between the wear sleeve 152
and the bore 150.
The one-piece housing 3" of FIG. 9 also carries an integral,
threaded hub 170 at its rearward end which may conveniently be
secured to a handle or other mounting means. Disassembly of the
nozzle elements and any such handle or other mounting means is
rapid and compact transport of the device is achieved with relative
ease and simplicity.
By way of example, in applying the invention to apparatus to be
handled by one man in cutting rock, concrete and other hard
materials in place of the conventional jackhammer, pressurized
water at about 20,000 pounds per square inch can be supplied to a
chamber having an inside diameter of about 8 inches. Such pressure
would result in a compression of water of about 5% and would eject
slugs of water having a volume of about 13 cubic inches into the
nozzle with a pulse energy of about 10,000 foot-pounds each. At the
pressure given, the chamber housing stretches, thereby storing
additional recoverable energy. For a spherical chamber made of
titanium, which has a low value of modulus of elasticity compared
to steel, the energy stored in the wall could easily amount to over
1000 foot-pounds, allowing significantly increased total pulse
energy without increased water consumption. Said sphere could weigh
less than forty pounds and would be very corrosion resistant.
The above figures are exemplary only and are not to be considered
as limiting. In addition, application of the invention is not
limited to hand held devices for cutting hard substances, but it
may be used in many applications where single or repetitive, high
energy pulsed liquid jets are useful. In fact, those skilled in the
art will appreciate that various combinations of and modifications
and alternatives to the examples given could be developed in light
of the overall teachings of the disclosure. Accordingly, the
particular arrangements and applications disclosed are meant to be
illustrative only and not limiting as to the scope of the invention
which is to be given the full breadth of the appended claims and
any and all equivalents thereof.
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